Membrane keyboard/keypad with arrangement for uniformly lighting keys from background

A membrane keyboard for a notebook computer, comprising:

• a frame board comprising a plurality of units each having a central aperture;
• a plurality of transparent keys each comprising a bottom press portion;
• a plurality of resilient bridge structures disposed on the frame board, each of the bridge structures being secured to the bottom of the corresponding key and comprising a central opening;
• a plurality of resilient insulative elastic members each comprising a downward stem and a top cup-shaped member;
• a film circuit board comprising a plurality of LEDs;
• a light guide film plate formed of transparent elastomeric material, the light guide film plate being fastened on the film circuit board and comprising a plurality of light diffusing areas on the bottom, each light diffusing area being disposed a predetermined distance under the corresponding key and having a plurality of cavities and a conductive member raised downward from a center of the cavities wherein the cavities are different in terms of depth, size, and density corresponding to different distances from the LEDs;
• and
• a base board with the film circuit board fastened thereon,
• wherein the elastic members are secured onto the light diffusing areas respectively and are inserted through the apertures and the openings with the cup-shaped members being securely put on the press portions so that the keys are adapted to light uniformly when the notebook computer is activated.